1. Field of the Invention
The present invention relates to an apparatus and method for processing video signals, and more specifically, to an apparatus and a method for processing digital video disk (DVD) subpicture formatted information within a television signal.
2. Description of the Background Art
Most digital satellite, digital cable television set top boxes and digital over-the-air television receivers decode moving pictures experts group (MPEG)-compliant signals, ISO/IEC International Standards 11172 (1991) (generally referred to as MPEG-1) and 13818 (1995) (generally referred to as MPEG-2), to recover audio and video information therefrom. These signals comprise encoded bitstreams containing coded representations of a plurality of images, and audio and control information associated with the images. The bitstreams are generated by an encoder system and transmitted to a decoding system through a communications channel.
In addition to audio and video information, an MPEG-compliant signal is capable of carrying data services on a data service channel such that the receiver can display stock prices, weather information, sports scores, electronic program guide information, top news stories and the like. This data channel information is presented using the on-screen display (OSD) functions of the MPEG decoder.
However, the OSD functionality of an MPEG decoder has a very limited capability to display graphics. The data service channel is generally limited to the display of text information that scrolls along the bottom of a video image. As such, non-text information such as complex graphics or animation generally cannot be decoded and displayed using the OSD functions of the MPEG decoder. Also, MPEG-based graphics do not facilitate interactivity with a viewer.
Therefore, there is a need in the art for a method and apparatus for transmitting, decoding and displaying data channel information in a format that permits enhanced graphics functionality as compared to a graphics display system based on an MPEG decoder.